As per this report, stacked magic items now get automatically /own'd and given the same item ID. I mentioned this to @ClarinetPhoenix who said this could cause major issues in regards to selling the item at one point. I have already resolved this issue with @ClarinetPhoenix privately after creating this report.
Thanks for reporting! We have added this to our bug tracker. In the meantime please have @ClarinetPhoenix replace these for anyone who is experiencing this issue.
